Image generating apparatus and image display system

ABSTRACT

A technology for intuitively recognizing a positional relation between a vehicle and an object is provided. In an image display system, in a display image provided to a driver, the side region of the vehicle in a direction indicated by a direction instructing device is displayed in large size. Accordingly, the object that may contact with the vehicle is easily found out, so that a minor crash accident can be effectively prevented. Since a synthetic image viewed from a virtual viewpoint directed from a rear position of the vehicle toward the front side of the vehicle is displayed, the side area of the vehicle is displayed in the same visual field direction as the direction of the visual field of the driver. Accordingly, the driver can intuitively recognize the positional relation between the vehicle and the object, without undertaking complicated determination such as conducting coordinate transformation in his/her mind.

BACKGROUND FIELD

The present invention relates to a technology for displaying an image tobe displayed on a display apparatus mounted on a vehicle.

RELATED ART

An image display system of a related art is mounted on a vehicle such asa car, and captures the periphery of the vehicle to generate an imageand display the image in a display in the inside of the vehicle. Forexample, an outside area of a front fender, which is opposite to adriver's seat, can be easily blinded. By using the image display systemthat displays an image obtained by capturing the outside area of thefront fender, the driver can easily recognize clearance between thevehicle body opposite to the driver's seat and an obstacle when thevehicle passes by an oncoming vehicle on a narrow road or in othercases.

There has been suggested a technology for displaying an image showing abroad area of the vehicle periphery, and not a limited area of thevehicle periphery such as the outside area of the front fender, in theinside of the vehicle. For example, Patent Document 1 arranges anddisplays three images obtained by vehicle mounting cameras, which areprovided on a front side and left and right sides of the vehicle,respectively, on one screen,

Patent Document 2 suggests a technology for providing an image showingthe periphery of the vehicle viewed from a virtual viewpoint setsubstantially directly above the vehicle, by using a plurality ofcaptured images obtained from capturing the periphery of the vehicle bymeans of a plurality of vehicle mounting cameras. Patent Document 2 alsosuggests a technology for moving a position of a driver's own vehicle inan image in accordance with a direction indicated by a directionindication.

RELATED ART Patent Documents

Patent Document 1: Japanese Patent Application Publication No.2001-114048

Patent Document 2: Japanese Patent Application Publication No. Hei3-99952

DISCLOSURE OF THE INVENTION Technical Problem to be Solved by theInvention

In the image display system of the related art, a visual field directionof a viewpoint looking an object displayed in an image to be displayedis a direction of an optical axis of the vehicle mounting cameras, or adirection looking down the vehicle from substantially directly above thevehicle. Accordingly, the driver sees the image and recognizes apositional relation between an actual object and the vehicle through athinking process, i.e., conducting coordinate transformation in his/hermind, based on the position of the object in the image. However, it isdifficult to determine the positional relation between the actual objectand the vehicle in a moment.

As in Patent Document 1, in case of displaying the front side and theleft and right sides of the vehicle on one screen, the image showing thefront side of the vehicle and the image showing the sides of the vehicleare different in terms of a visual field direction. Accordingly, thedriver may be confused of a direction toward which an object exists, sothat the driver cannot determine the positional relation between theobject and the vehicle in a moment.

However, when the driver who drives the vehicle finds out an object thatmay contact with the vehicle, he/she needs to conduct avoidance drivingto avoid crash by a momentary decision. However, in the conventionalimage display system, it is difficult to determine the positionalrelation between the vehicle and an object around the vehicle in amoment. Accordingly, there is a case where making an exact decision in amoment is difficult. Accordingly, a technology for more intuitivelyrecognizing the positional relation between the vehicle and an objecthas been demanded.

The present invention has been made in consideration of thecircumstances, and its object is to provide a technology for intuitivelyrecognizing a positional relation between a vehicle and an object.

The object of the present invention is accomplished by the configurationset forth below.

(1) An image generating apparatus that generates an image to bedisplayed on a display apparatus mounted on a vehicle, the imagegenerating apparatus comprising: a synthetic image generating sectionthat generates a synthetic image around the vehicle based on a pluralityof images of the periphery of the vehicle took by a plurality ofcameras, the synthetic image being viewed from a virtual viewpoint whichis disposed behind the vehicle and is directed to the front side of thevehicle; an output section that outputs the generated synthetic image tothe display apparatus; and an input section that inputs a directionindication of a driver of the vehicle, wherein the synthetic imagegenerating section: generates a first synthetic image in which left sidearea of the vehicle is displayed in substantially the same size as rightside area of the vehicle when the direction indication is not input bythe input section; and generates a second synthetic image in which oneside area of the vehicle, which is indicated by the direction indicationis displayed larger in size than another side area of the vehicle whenthe direction indication is input by the input section.

(2) The image generating apparatus as set forth in (1) above, whereinthe synthetic image generating section continues to generate the secondsynthetic image for a predetermined period when the input section stopsinputting the direction indication, and wherein the synthetic imagegenerating section starts generating the first synthetic image after thepredetermined period when the direction indication is not input duringthe predetermined period.

(3) The image generating apparatus as set forth in (1) or (2) above,further comprising a display image generating section that generates adisplay image including a front image took by a camera provided at thefront side of the vehicle and the synthetic image generated by thesynthetic image generating section, wherein the output section outputsthe generated display image to the display apparatus.

(4) The image generating apparatus as set forth in any one of (1) to (3)above, wherein when changing the virtual viewpoint of the syntheticimage from a first position to a second position, the synthetic imagegenerating section moves the virtual viewpoint from the first positionto the second position in a stepwise manner to generate a plurality ofsynthetic images for creating an animation in which the virtualviewpoint is moved in a continuous manner.

(5) An image generating apparatus that generates an image to bedisplayed on a display apparatus mounted on a vehicle, the imagegenerating apparatus comprising: a synthetic image generating sectionthat generates a synthetic image around the vehicle based on a pluralityof images of the periphery of the vehicle took by a plurality ofcameras, the synthetic image being viewed from a virtual viewpoint whichis disposed behind the vehicle and is directed to the front side of thevehicle, and including a right side area and a left side area of thevehicle; a display image generating section that generates a displayimage including a front image took by a camera provided at the frontside of the vehicle and the synthetic image generated by the syntheticimage generating section; and an output section that outputs thegenerated display image to the display apparatus.

(6) An image generating apparatus that generates an image to bedisplayed on a display apparatus mounted on a vehicle, the imagegenerating apparatus comprising: a synthetic image generating sectionthat generates a synthetic image being viewed from a virtual viewpointbased on a plurality of images of the periphery of the vehicle took by aplurality of cameras; and an output section that outputs the generatedsynthetic image to the display apparatus, wherein when changing thevirtual viewpoint of the synthetic image from a first position to asecond position, the synthetic image generating section moves thevirtual viewpoint from the first position to the second position in astepwise manner to generate a plurality of synthetic images for creatingan animation in which the virtual viewpoint is moved in a continuousmanner.

(7) The image generating apparatus as set forth in (6) above, whereinthe synthetic image generating section changes the virtual viewpointfrom a reference position.

(8) The image generating apparatus as set forth in (7) above, whereinthe reference position is a position corresponding to a viewpoint of adriver of the vehicle.

(9) An image display system to be mounted on a vehicle, the imagedisplaying system comprising: the image generating apparatus as setforth in any one of (1) to (8) above; and a display apparatus thatdisplays an image generated by the image generating apparatus.

Effect of the Invention

The image generating apparatus set forth in (1) to (4) above and theimage display system set forth in (9) above widely display a side areain a direction intended by the driver, where there is most likely anobject, with which the vehicle may contact when the vehicle moves uponchanging a direction or moving toward a roadside. Accordingly, theobject that may contact with the vehicle is easily found out, so that aminor crash accident can be effectively prevented. Since a syntheticimage viewed from a virtual viewpoint directed from a rear position ofthe vehicle toward the front side of the vehicle is displayed, the sidearea of the vehicle is displayed in the same visual field direction asthe direction of the visual field of the driver. Accordingly, the drivercan intuitively recognize the positional relation between the vehicleand the object, without undertaking complicated determination such asconducting coordinate transformation in his/her mind.

According to the image generating apparatus set forth in (2) above, itis possible to prevent the occasion that seeing a synthetic imagedisplayed on a display apparatus is difficult because a viewpoint of thesynthetic image is frequently changed when the direction indication iscontinuously operated in short time, or in other cases.

According to the image generating apparatus set forth in (3) above, thedisplay apparatus displays the front area and the left and right sideareas of the vehicle on the same screen. Accordingly, an area that thedriver desires to monitor upon driving can be monitored from the samescreen without changing the screen. Since the visual field direction ofthe front image, the visual field direction of the synthetic image, andthe visual field direction of the driver are substantially identical,the driver can intuitively recognize the positional relation of anobject displayed on the screen, without undertaking complicateddetermination such as conducting coordinate transformation in his/hermind. Accordingly, even if much information has been provided, thedriver can make an exact decision, so that safety can be assured.

According to the image generating apparatus set forth in (4) above,animation expression of a synthetic image, in which a virtual viewpointis moved in a continuous manner from a first position to a secondposition, is created on the display apparatus. As such, compared to thecase where the virtual viewpoint is converted from the first position tothe second position in a moment, the driver can easily intuitivelyrecognize the position of the virtual viewpoint of the synthetic imageafter the conversion of the virtual viewpoint.

According to the image generating apparatus set forth in (5) above,since the display apparatus displays the front area and the left andright side areas of the vehicle on the same screen, an area that thedriver desires to monitor can be monitored from the same screen withoutchanging the screen. Since the visual field direction of the frontimage, the visual field direction of the synthetic image, and the visualfield direction of the driver are substantially the same, the driver canintuitively recognize the positional relation of the object displayed onthe screen, without undertaking complicated determination such asconducting coordinate transformation in his/her mind. Accordingly, evenif much information has been provided, the driver can make an exactdecision, so that safety can be assured,

According to the image generating apparatus set forth in (6) to (8),animation expression of a synthetic image, in which the virtualviewpoint is moved from the first position to the second position on thedisplay apparatus, is created on the display apparatus. Accordingly,compared to the case where the virtual viewpoint moves from the firstposition to the second position in a moment, the driver can easilyintuitively recognize the position of the virtual viewpoint of thesynthetic image after the conversion of the virtual viewpoint.

According to the image generating apparatus set forth in (7), since thevirtual viewpoint moves from a reference position, the driver can easilyintuitively recognize the position of the virtual viewpoint of thesynthetic image after the conversion of the virtual viewpoint withrespect to the relation with the reference position.

According to the image generating apparatus set forth in (8), since thevirtual viewpoint moves from a reference position corresponding to theviewpoint of the driver, the driver can more easily intuitivelyrecognize the position of the virtual viewpoint of the synthetic imageafter the conversion of the virtual viewpoint.

BRIEF DESCRIPTIONS OF THE DRAWINGS

FIG. 1 is a block view of an image display system.

FIG. 2 is a view showing positions where vehicle mounting cameras aredisposed on a vehicle.

FIG. 3 is an explanatory view of a method for generating a syntheticimage viewed from a virtual viewpoint.

FIG. 4 is a view showing transition of an operation mode of the imagedisplay system.

FIG. 5 is a view showing transition of a display mode in a front mode.

FIG. 6 is a view showing an example of a display image of a binary imagemode.

FIG. 7 is an explanatory view of a visual field scope presented in abinary image mode.

FIG. 8 is a view showing an example of screen display in a binary imagemode.

FIG. 9 is a view showing transition of a viewpoint position of a virtualviewpoint.

FIG. 10 is a view showing an example of a display image of a binaryimage mode.

FIG. 11 is a view showing an example of a display image of a binaryimage mode.

FIG. 12 is a view showing flow of processing to change a viewpointposition of a virtual viewpoint.

FIG. 13 is a view showing an example of screen display in a single imagemode.

FIG. 14 is a view showing movement of a virtual viewpoint.

FIG. 15 is a view showing an example of screen display in a side cameramode.

FIG. 16 is a view showing transition of a display mode in a back mode.

FIG. 17 is a view showing a horizontal angle of a visual field scope ofa standard mode.

FIG. 18 is a view showing a horizontal angle of a visual field scope ofa wide mode.

FIG. 19 is a view showing an example of a display image of a syntheticstandard mode.

FIG. 20 is a view showing an example of a display image of a synthetichigh angle mode.

FIG. 21 is a view showing a viewpoint position of a virtual viewpoint ofa synthetic high angle mode.

FIG. 22 is a view showing a setting screen of a virtual viewpoint.

FIG. 23 is a view showing a setting screen of a virtual viewpoint.

FIG. 24 is a view showing an example of a display image of a syntheticstandard mode.

FIG. 25 is a view showing processing flow to store mode information.

FIG. 26 is a view showing processing flow of time to start a back mode.

FIG. 27 is a view showing processing flow to store mode information.

FIG. 28 is a view showing processing flow of time to start a back mode.

BEST MODE TO CARRY OUT THE INVENTION

Hereinafter, an embodiment of the present invention will be describedwith reference to the drawings.

1. Configuration

FIG. 1 is a block view of an image display system 100 according to anembodiment of the present invention. The image display system 100 ismounted on a vehicle (a ear in the present embodiment) and has afunction of capturing the periphery of the vehicle to generate an imageand display the image in the inside of the vehicle. A user of the imagedisplay system 100 who is a driver of the vehicle can easily monitor theperiphery of the vehicle by using the image display system 100.

As illustrated in FIG. 1, the image display system 100 includes acapturing section 5 that captures the periphery of the vehicle, an imagegenerating apparatus 10 that generates a display image showing theperiphery of the vehicle, and a navigation apparatus 20 that providesvarious information to the driver of the vehicle. The image generatingapparatus 10 is configured by ECU (Electronic Control Unit) having animage generating function and disposed at a predetermined position ofthe vehicle.

The navigation apparatus 20 carries out navigation guide to the driver.The navigation apparatus 20 includes a display 21 such as a liquidcrystal that has a touch panel function, an operating section 22 that isoperated by the driver, and a control section 23 that controls theapparatus as a whole. The navigation apparatus 20 is provided on aninstrument panel or others of the vehicle so that the screen of thedisplay 21 can be seen from the driver. Various instructions from thedriver are received by the operating section 22 and the display 21 as atouch panel. The control section 23 is configured by a computer havingCPU, RAM, ROM, and others. Various functions including the navigationfunction are accomplished in the manner that the CPU carries outcalculation processing in accordance with predetermined programs.

The navigation apparatus 20 is communicably connected to the imagegenerating apparatus 10. The navigation apparatus 20 can transmit andreceive various control signals with the image generating apparatus 10or receive a display image generated in the image generating apparatus10. The display 21 usually displays a map image for navigation guide.However, the display 21 displays a display image generated in the imagegenerating apparatus 10 and showing the vehicle periphery, in responseto predetermined operation by the driver or a signal or others from theimage generating apparatus 10. Accordingly, the navigation apparatus 20also functions as a display apparatus that receives a display imagegenerated in the image generating apparatus 10 and displays the image.

The capturing section 5 is electrically connected to the imagegenerating apparatus 10 and operated based on a signal from the imagegenerating apparatus 10. The capturing section 5 includes vehiclemonitoring cameras, i.e., a front camera 51, side cameras 52, and a backcamera 53. The vehicle mounting cameras 51, 52, and 53 include lensesand imaging elements and electronically acquire images.

FIG. 2 is a view showing positions where the vehicle mounting cameras51, 52, and 53 are disposed on the vehicle 9. As illustrated in FIG. 2,the front camera 51 is provided near a position where a number plate isprovided at the front end of the vehicle 9. An optical axis 51 a of thefront camera 51 is toward the straight direction of the vehicle 9. Theside cameras 52 are provided on left and right door mirrors 93,respectively. Optical axes 52 a of the side cameras 52 are toward anoutside direction of the vehicle 9 to be orthogonal to the straightdirection. The back camera 53 is provided near a position where a numberplate is provided at the rear end of the vehicle 9. An optical axis 53 aof the back camera 53 is toward a reverse direction of the straightdirection of the vehicle 9. The front camera 51 or the back camera 53 ispreferably provided in substantially a center of the left and the right,but may be positioned somewhat out of the center of the left and theright toward the left or right direction.

For the lenses of the vehicle mounting cameras 51, 52, and 53, fish-eyelenses or others are adopted. The vehicle mounting cameras 51, 52, and53 have at least 180° of an angle of view α. Accordingly, if the fourvehicle mounting cameras 51, 52, and 53 are used, it is possible tocapture the entire circumference of the vehicle 9.

Returning to FIG. 1, the image generating apparatus 10 includes acontrol section 1 that controls the apparatus as a whole, an imageprocessing section 3 that processes a captured image acquired from thecapturing section 5 and generates a display image, and a communicationsection 42 that communicates with the navigation apparatus 20. Variousinstructions received from the driver through the operating section 22or the display 21 of the navigation apparatus 20 are received by thecommunication section 42 as control signals and input into the controlsection 1. Accordingly, the image generating apparatus 10 can implementoperation in response to the driver's operation to the navigationapparatus 20.

The image processing section 3 is configured by a hardware circuitcapable of processing various images and includes a captured imageadjusting section 31, a synthetic image generating section 32, and adisplay image generating section 33 as main functions. The capturedimage adjusting section 31 adjusts a captured image acquired from thecapturing section 5 to be a display image. The captured image adjustingsection 31 implements adjustment of image quality of a captured imagesuch as brightness or contrast, distortion amendment of an image so thatthe image is naturally displayed, or others. The synthetic imagegenerating section 32 generates a synthetic image viewed from a certainvirtual viewpoint in the vicinity of the vehicle 9, based on a pluralityof captured images that have been acquired from the plurality of vehiclemounting cameras 51, 52, and 53 of the capturing section 5. How thesynthetic image generating section 32 generates a synthetic image viewedfrom a virtual viewpoint will be described hereafter.

The display image generating section 33 generates a display image to beprovided to the driver, by using one or combination of a plurality ofimages from the captured images that have been adjusted in the capturedimage adjusting section 31 and the synthetic images that have beengenerated by the synthetic image generating section 32. The generateddisplay image is output to the navigation apparatus 20 by thecommunication section 42, and displayed on the display 21 of thenavigation apparatus 20.

The control section 1 is configured by a computer having CPU, RAM, ROM,and others. Various control functions are accomplished in the mannerthat the CPU carries out calculation processing in accordance withpredetermined programs. The functions of the control section 1 that areaccomplished as described above include a function of controlling imageprocessing that is implemented by the image processing section 3, i.e.,a function of controlling contents of a display image. Variousparameters needed to generate synthetic images in the synthetic imagegenerating section 32 are instructed by the functions of the controlsection 1. The control section 1 also includes a non-volatile memory 11configured by a flash memory or others, and a timer 12 having ameasuring function.

The image generating apparatus 10 also includes a signal input section41 that inputs signals from various apparatuses provided in the vehicle9. Signals from the outside of the vehicle 9 are input to the controlsection 1, through the signal input section 41. Specifically, signalspresenting various information are input from a shift sensor 81, avehicle speed sensor 82, a direction instructing device 83, a steeringsensor 84, a converting switch 85, and others to the control section 1.Meanwhile, the image display system 100 may be configured to includeparts or all of the shift sensor 81, the vehicle speed sensor 82, thedirection instructing device 83, the steering sensor 84, and theconverting switch 85.

From the shift sensor 81, a position of operation of a shift lever inthe transmission of the vehicle 9, i.e., a shift position such as “P(parking),” “D (driving),” “N (neutral),” or “R (reversing)” is input.From the vehicle speed sensor 82, a driving speed (km/h) of the vehicle9 at that time is input.

From the direction instructing device 83, a direction instruction basedon operation of a winker switch, i.e., a turn signal presenting adirection instruction intended by the driver of the vehicle 9 is input.When the winker switch is operated, a turn signal is generated. The turnsignal presents the operated direction (left or right direction). Whenthe winker switch is in a neutral position, the turn signal is off.

From the steering sensor 84, a direction of rotation of a steering wheelby the driver and an angle of the rotation are input. The convertingswitch 85 is a switch that receives an instruction to convert an aspectof a display image from the driver. From the converting switch 85, asignal presenting an instruction of the driver is input to the controlsection 1.

2. Image Conversion Processing

Next, how the synthetic image generating section 32 of the imageprocessing section 3 generates a synthetic image viewed from a certainvirtual viewpoint based on a plurality of captured images that have beenobtained from the capturing section 5. FIG. 3 is an explanatory view ofa method of generating a synthetic image viewed from a certain virtualviewpoint.

When the front camera 51, the side cameras 52, and the back camera 53 ofthe capturing section 5 capture images at the same time, four capturedimages P1 to P4 presenting the front side, the left and rightdirections, and the rear side of the vehicle 9, respectively, areacquired. That is, the four captured images P1 to P4 acquired from thecapturing section 5 include information presenting the entirecircumference of the vehicle 9 at the capturing time.

After the four captured images P1 to P4 are multiplexed, they areprojected onto an imaginary three-dimensional curved surface SP. Forexample, the three-dimensional curved surface SP is substantially in ahemisphere (bowl) shape. The central part of the three-dimensionalcurved surface SP (bottom part of a bowl) is set as a position of thevehicle 9. A corresponding relation between a position of each pixelincluded in the captured images P1 to P4 and a position of each pixel ofthe three-dimensional curved surface SP is predetermined. Accordingly, avalue for each pixel of the three-dimensional curved surface SP can bedetermined based on the corresponding relation and a value for eachpixel included in the captured images P1 to P4. The correspondingrelation between a position of each pixel of the captured images P1 toP4 and a position of each pixel of the three-dimensional curved surfaceSP is stored as table data in the non-volatile memory 11 of the controlsection 1 or others.

Meanwhile, a virtual viewpoint VP to the three-dimensional curvedsurface SP is set by the control section 1 at a certain viewpointposition in the vicinity of the vehicle toward a certain visual fielddirection. The virtual viewpoint VP is defined with the viewpointposition and the visual field direction. In accordance with the setvirtual viewpoint VP, a necessary area on the three-dimensional curvedsurface SP is cut out as an image, so that a synthetic image viewed fromthe certain virtual viewpoint is generated.

For example, in case of setting a virtual viewpoint VP1, in which theviewpoint position is a position directly above substantially a centerof the vehicle 9, and the visual field direction is substantially adirect downward direction, a synthetic image CP1 looking down thevehicle 9 from substantially directly above the vehicle 9 is generated.As illustrated in the same drawing, in case of setting a virtualviewpoint VP2, in which the viewpoint position is a left rear positionof the vehicle 9, and the visual field direction is substantially afront direction of the vehicle 9, a synthetic image CP2 looking theentire periphery of the vehicle 9 from the left rear side of the vehicle9 is generated. A relation between the virtual viewpoint VP and thenecessary area on the three-dimensional curved surface SP ispredetermined and stored as table data in the non-volatile memory 11 ofthe control section 1.

When a synthetic image is actually generated, there is no need todetermine values for all pixels of the three-dimensional curved surfaceSP. Values only for pixels of the necessary area in correspondence tothe set virtual viewpoint VP is determined based on the captured imagesP1 to P4, thereby increasing the processing speed.

An image of the vehicle 9 to be presented in a synthetic image isprepared in advance as data such as a bit map and stored in thenon-volatile memory 11 or others. When a synthetic image is generated,data for the image of the vehicle 9 in the shape in accordance with theviewpoint position and the visual field direction of the virtualviewpoint VP of the synthetic image as described above are read, so thatthey are overlapped within the synthetic image. Meanwhile, in thedrawing, the actual vehicle and the image of the vehicle to be presentedin an image are denoted by the same reference numeral 9.

3. Operation Mode

Next, operation of the image display system 100 will be described. FIG.4 is a view showing transition of an operation mode of the image displaysystem 100. The image display system 100 has three operation modes thatinclude a navi mode M0, a front mode M1, and a back mode M2. Theoperation modes are converted by control of the control section 1 inaccordance with operation by the driver or a driving state.

The navi mode M0 is an operation mode that displays a map image fornavigation guide or others on the display 21, through the function ofthe navigation apparatus 20. In the navi mode M0, the functions of thecapturing section 5 and the image generating apparatus 10 are not used.Various displays are accomplished by the function of the navigationapparatus 20 as a single unit. Accordingly, if the navigation apparatus20 has a function of receiving and displaying a TV broadcasting radiowave, instead of the map image for navigation guide, a TV broadcastingscreen may be displayed.

The front mode M1 and the back mode M2 are operation modes that displaya display image presenting peripheral circumferences of the vehicle 9 inreal time on the display 21, by using the functions of the capturingsection 5 and the image generating apparatus 10. The front mode M1 is anoperation mode that effectuates a function of a front monitor to displaya display image primarily presenting a front region or a side region ofthe vehicle 9, which is necessary upon advancing the vehicle 9. The backmode M2 is an operation mode that effectuates a function of a backmonitor to display a display image primarily presenting a rear region ofthe vehicle 9, which is necessary upon reversing the vehicle 9.

In case of the navi mode M0, for example, if the driving speed inputfrom the vehicle speed sensor 82 is less than 10 km/h, the navi mode M0is converted into the front mode M1. In case of the front mode M1, forexample, if the driving speed is at least 10 km/h, the front mode M1 isconverted into the navi mode M0.

If the driving speed of the vehicle 9 is relatively high, the front modeM1 is released to enable the driver to concentrate on the driving.Reversely, if the driving speed of the vehicle 9 is relatively low, itis highly likely that the driver is performing driving in considerationof peripheral circumstances of the vehicle 9, e.g., entering into acrossroad where views are poor, changing a direction, and moving towarda roadside. Accordingly, when the driving speed is relatively low, theoperation mode is converted into the front mode M1 primarily presentinga front region or a side region of the vehicle 9. Meanwhile, in the casewhere the operation mode is converted from the navi mode M0 into thefront mode M1, a condition that an explicit operation instruction hasbeen made from the driver may be added to the condition that the drivingspeed is less than 10 km/h.

In case of the navi mode M0 or the front mode M1, if a position of theshift lever input from the shift sensor 81 is “R (reversing),” the navimode M0 or the front mode M1 is converted into the back mode M2. Inother words, when the transmission of the vehicle 9 is operated to bepositioned at “R (reversing),” the vehicle 9 is in the reversing state,so that the operation mode is converted into the back mode M2 primarilypresenting a rear region of the vehicle 9.

In case of the back mode M2, when the position of the shift lever is aposition other than “R (reversing),” the back mode M2 is converted intothe navi mode M0 or the front mode M1 depending on the driving speed atthat time. If the driving speed is at least 10 km/h, the back mode M2 isconverted into the navi mode M0. If the driving speed is less than 10km/h, the back mode M2 is converted into the front mode M1.

Hereinafter, an aspect for displaying the periphery of the vehicle 9 ineach of the front mode M1 and the back mode M2 will be described indetail.

4. Front Mode

First, a display aspect of the front mode M1 will be described. FIG. 5is a view showing transition of a display mode in the front mode M1. Thefront mode M1 includes three display modes, i.e., a binary image modeM11, a single image mode M12, and a side camera mode M13. The displaymodes are different in a display aspect. Each time the driver pressesthe converting switch 85, the display modes are converted into thebinary image mode M11, the single image mode M12, and the side cameramode M13 in this order by control of the control section 1. In case ofthe side camera mode M13, when the converting switch 85 is pressed, theside camera mode 13 is returned again to the binary image mode M11.

The binary image mode M11 is a display mode that displays a displayimage including a front image FP1 obtained from capturing in the frontcamera 51 and a synthetic image FP2 viewed from the virtual viewpoint VPside by side on the display 21. In the binary image mode M11, twoimages, i.e., the front image FP1 and the synthetic image FP2 aredisplayed on the same screen.

The single image mode M12 is a display mode that displays a displayimage including only a synthetic image FP3 viewed from the virtualviewpoint VP on the display 21. The side camera mode M13 is a displaymode that displays a display image including only a side image FP4obtained from capturing in the side cameras 52 on the display 21.

4-1.2 Image Mode 4-1-1. Visual Field Scope

In the binary image mode M11, the display image generating sectiongenerates the display image including the front image FP1 captured bythe front camera 51 and the synthetic image FP2 generated by thesynthetic image generating section 32 and the communication section 42outputs the generated display image to the navigation apparatus 20.

FIG. 6 is a view showing an example of a display image to be displayedon the display 21 in the binary image mode M11. As illustrated in FIG.6, on a display image of the binary image mode M11, a front image FP1 isdisposed at an upper part, and a synthetic image FP2 is disposed at alower part. The front image FP1 is not a synthetic image from thevirtual viewpoint VP, but is a display image obtained in the manner thata captured image obtained from capturing in the front camera 51 isadjusted in the image adjusting section 31 to be a display image. Thesynthetic image FP2 is a synthetic image that includes the side regionof the vehicle 9 viewed from the virtual viewpoint VP directed from therear position of the vehicle 9 toward the front of the vehicle 9.

FIG. 7 is an explanatory view of a visual field scope presented in thebinary image mode M11 in the vicinity of the vehicle 9. In FIG. 7, ascope FV1 presented by a dashed line is a visual field scope presentedon the front image FP1. A scope FV2 presented by a chain double-dashedline is a visual field scope presented on the synthetic image FP2. Thevisual field scopes FV1 and FV2 partially overlap with each other in anarea A2, which is a boundary of the scopes.

On the front image FP1, an area of a 180° horizontal angle expanded inthe left and right direction in the front region of the vehicle 9 is setas the visual field scope FV1. Accordingly, the driver sees the frontimage FP1 so that he/she can recognize an object existing in the leftand right front sides of the vehicle 9 that can be easily blinded whenentering into a crossroad where views are poor.

On the synthetic image FP2, a scope that includes the left and rightside regions of the vehicle 9 from the front of the front end of thevehicle 9 to the rear of the rear end of the vehicle 9, and the rearregion of the vehicle 9 is set as the visual field scope FV2.Accordingly, the driver sees the synthetic image FP2 so that he/she canrecognize an object existing in the side regions or the rear region.When performing changing a direction, moving toward a roadside, orothers, the driver can easily monitor an area that may be easily blindedfrom the driver's seat, e.g., an area A1 near the outside of a frontfender 94 that is not seen on the door mirror 93.

In the binary image mode M11, the two images FP1 and FP2 of the visualfield scopes FV1 and FV2 can be seen at the same time without convertinga screen (refer to FIG. 6), so that the driver can monitor peripheralcircumstances of the vehicle 9 at once.

The viewpoint position of the virtual viewpoint VP of the syntheticimage FP2 is set to the rear position of the vehicle 9. The visual fielddirection is set to the front direction of the vehicle 9. Accordingly,as illustrated in FIG. 6, the synthetic image FP2 shows the periphery ofthe vehicle 9 in the state that the vehicle 9 is viewed from the rearposition of the vehicle 9 toward the front direction, together with theimage of the vehicle 9. Since the visual field direction of the frontimage FP1, the visual field direction of the synthetic image FP2, andthe visual field direction of the driver are substantially identical,the driver is not confused of the direction toward which an objectpresented on the image exists. The driver does not need to makecomplicated thinking such as conducting coordinate transformation inhis/her mind, so that the driver can intuitively recognize thepositional relation between an object displayed on the display 21 andthe vehicle 9.

Compared to the case of using an image looking down the vehicle 9 fromdirectly above the vehicle 9, the positional relation regarding to whichportion of the vehicle 9 an object around the vehicle 9 is closed iseasily recognized. On the synthetic image FP2 viewed from the virtualviewpoint directed from the rear position of the vehicle 9 toward thefront direction, the front region that is an advancing direction of thevehicle 9, as well as the side region of the vehicle 9 are presented.Accordingly, compared to the case of using an image looking down thevehicle 9 from directly above the vehicle 9, it is easily predicted howthe positional relation between the vehicle 9 and an object around thevehicle 9 varies depending on advancing of the vehicle 9. Accordingly,when the vehicle 9 is advanced, the vehicle 9 is effectively preventedfrom contacting with an object around the vehicle 9.

As illustrated in FIG. 7, it is assumed that a certain object T movesaround the vehicle 9 over the visual field scopes FV1 and FV2 of the twoimages FP1 and FP2. Specifically, the object T moves from a position TP1out of the visual field scope of the binary image mode M11 to a positionTP2 of the area A1 within the visual field scope FV2, to a position TP3within the overlapping area A2 of the visual field scope FV1 and thevisual field scope FV2, and finally, to a position TP4 of the front sideof the vehicle 9 within the visual field scope FV1. FIG. 8 is a viewshowing an example of screen display of the display 21 in the binaryimage mode M11, in the case where the object T moves as described above.

When the object T moves from the position TP1 out of the visual fieldscope to the position TP2 within the visual field scope FV2 of thesynthetic image FP2, the object T first appears on the synthetic imageFP2 of the lower portion of the screen (state ST1). At this viewpoint,the object T has not appeared on the front image FP1 of the upperportion of the screen. Subsequently, when the object T moves to theposition TP3 within the overlapping area A2 of the visual field scopeFV1 and the visual field scope FV2, the object T appears on both thefront image FP1 and the synthetic image FP2 (state ST2). When the objectT moves into the position TP4 within the visual field scope FV1 of thefront image FP1, the object T appears on the front image FP1 (stateST3).

Even in the case where the object T moves over the visual field scopesFV1 and FV2 of the two images FP1 and FP2 around the vehicle 9, sincethe visual field direction of the front image FP1 and the visual fielddirection of the synthetic image FP2, and the visual field direction ofthe driver are substantially identical, the object T moves insubstantially the same direction on any of the two images FP1 and FP2,Accordingly, the driver can intuitively recognize the movement of theobject T. Since there is the area A2 that is a boundary where the visualfield scope FV1 and the visual field scope FV2 overlap with each other,there is a scene where the object T appears on both the front image FP1and the synthetic image FP2 at the same time. Accordingly, the movementof the object T can be recognized in a continuous manner.

In the binary image mode M11, much information is provided to thedriver. However, the driver can intuitively recognize peripheralcircumstances of the vehicle 9 as described above. Accordingly, thedriver can made an exact decision so that driving safety can besufficiently assured.

4-1-2. Interaction of Operation of a Direction Instructing Device

In the binary image mode M11, the viewpoint position of the virtualviewpoint VP of the synthetic image FP2 moves by control of the controlsection 1, in response to driver's operation to the winker switch of thedirection instructing device 83. FIG. 9 is a view showing transition ofthe viewpoint position of the virtual viewpoint VP.

If a turn signal input from the direction instructing device 83 is off,namely, the direction instruction is not input by the signal inputsection 41, the viewpoint position of the virtual viewpoint VP is set toa position VPC substantially in a center of the left and the right atthe rear of the vehicle 9, and the visual field direction is set to thefront direction of the vehicle 9. Accordingly, as illustrated in FIG. 6,the synthetic image FP2 in which the left side region of the vehicle 9is displayed in a size substantially equal to the right side region isgenerated.

If the turn signal input from the direction instructing device 83 is on,namely, the direction instruction is input by the signal input section41, the viewpoint position of the virtual viewpoint VP moves into theposition of the direction indicated by the turn signal, in the statethat the visual field direction of the virtual viewpoint VP is set tothe front direction of the vehicle 9. Specifically, if the turn signalindicates a left direction, the viewpoint position of the virtualviewpoint VP is set to a position VPL of the left side of the vehicle 9.Accordingly, as illustrated in FIG. 10, the synthetic image FP2 in whichthe left side region of the vehicle 9, indicated by the turn signal ofthe direction instructing device 83 is displayed in a size larger thanthe right side region is generated and displayed on the display 21. Inthis case as well, the synthetic image FP2 shows the periphery of thevehicle 9 in the state that the vehicle 9 is viewed from the rearposition of the vehicle 9 to the front direction.

If the turn signal indicates a right direction, the viewpoint positionof the virtual viewpoint VP is set to a position VPR of the right sideof the vehicle 9. Accordingly, as illustrated in FIG. 11, the syntheticimage FP2 in which the right side region of the vehicle 9, indicated bythe turn signal of the direction instructing device 83 is displayed in asize larger than the left side region is generated and displayed on thedisplay 21. In this case as well, the synthetic image FP2 shows theperiphery of the vehicle 9 in the state that the vehicle 9 is viewedfrom the rear position of the vehicle 9 to the front direction.

In the direction instructed by the direction instructing device 83,there is most likely an object, with which the vehicle 9 may contactwhen the vehicle 9 moves upon changing a direction or moving toward aroadside. The side region of the direction instructed by the directioninstructing device 83 is widely presented, so that the driver can payhis/her attention to the object with which the vehicle 9 may contact.Accordingly, the vehicle 9 can be effectively prevented from contactingwith the object.

In this case as well, the synthetic image FP2 shows the periphery of thevehicle 9 in the state that the vehicle 9 is viewed from the rearposition of the vehicle 9 to the front direction, together with theimage of the vehicle 9. Since the side region of the vehicle 9 appearsin the same visual field direction as the visual field direction of thedriver, the driver is not confused of the direction, toward which anobject presented in an image exists. The driver does not makecomplicated thinking such as conducting coordinate transformation inhis/her mind, so that the driver can intuitively recognize thepositional relation between the vehicle 9 and an object. In addition,the driver can easily recognize the positional relation regarding towhich portion of the vehicle 9 an object around the vehicle 9 is closed.The driver can easily predict how the positional relation between thevehicle 9 and an object around the vehicle 9 varies depending on drivingof the vehicle 9. Accordingly, the driver can make an exact decision ina moment.

Even in the case where the viewpoint position of the virtual viewpointVP is moved to the left or right side of the vehicle 9, the syntheticimage also includes a side region in a reverse direction to onedirection indicated by the turn signal. Accordingly, even if an objecthas existed in a side region in a reverse direction to a directionindicated by the turn signal, the object can be recognized. For example,in the case of temporarily operating the steering wheel in a reversedirection to a direction indicated by the turn signal in order to avoidan object existing in the direction indicated by the turn signal, it ispossible to prevent contact with an object existing in the reversedirection.

However, if the winker switch is returned from the operation position tothe neutral position, so that the turn signal from the directioninstructing device 83 is converted from on to off, the viewpointposition of the virtual viewpoint VP of the synthetic image FP2 isreturned to the position VPC substantially in a center of the left andthe right. In this case, when the input signal section 41 stopsinputting the direction instruction, the synthetic image generatingsection 32 continues to generate the synthetic image FP2 for apredetermined time. And the direction instruction is not input for thepredetermined time, the synthetic image generating section 32 startsgenerating the synthetic image FP1 after the predetermined time. Thatis, the viewpoint position of the virtual viewpoint VP is returned tothe position VPC substantially in a center of the left and the right,after a predetermined time elapses while the turn signal is off, and notimmediately after a turn signal is converted from on to off.

FIG. 12 is a view showing flow of processing for changing the viewpointposition of the virtual viewpoint VP. This processing is carried out bycontrol of the control section 1 when the winker switch is operated suchthat the turn signal is on.

First, a direction indicated by the turn signal of the directioninstructing device 83 is determined (S11). If the turn signal indicatesa left direction, S12 is carried out. If the turn signal indicates aright direction, S17 is carried out.

In S12, the virtual viewpoint VP is set to the position VPL of the leftside. Accordingly, as illustrated in FIG. 10, the synthetic image FP2that more widely shows the side region of the left direction than theright direction is generated and displayed on the display 21.

Subsequently, in the state that the virtual viewpoint VP is set to theposition VPL of the left side, the turn signal state is monitored (S13).If the state that the turn signal indicates a left direction has beenmaintained, the processing is returned to S12 so that the virtualviewpoint VP is maintained as the position VPL of the left side. Inother words, displaying the synthetic image FP2 that relatively widelyshows the side region of the left direction is maintained. Meanwhile, ifthe turn signal indicates a right direction, S17 is carried out.

In S13, if the turn signal is off, namely, a direction instruction hasbeen changed into no direction instruction, measuring by a timer 12 atthe time that the turn signal becomes off is started (S14).

The turn signal state is monitored, until a predetermined time elapsesfrom the starting of the measuring (S15 and S16), In the presentembodiment, for example, the predetermined time is three seconds. Untilthe predetermined time elapses, the virtual viewpoint VP is maintainedas the position VPL of the left side. And, displaying the syntheticimage FP2 that relatively widely shows the side region of the leftdirection is maintained. If the predetermined time elapses in the statethat the turn signal is off (Yes in S16), the viewpoint position of thevirtual viewpoint VP is returned to the position VPC substantially in acenter of the left and the right (S22). Accordingly, the synthetic imageFP2 that substantially equally includes the left and right side regionsof the vehicle 9 is displayed.

However, if the turn signal indicates a left direction again in S15,until the predetermined time elapses from the starting of the measuring,the processing is returned to S12 so that the state that the virtualviewpoint VP is the position VPL of the left side is maintained. Inother words, displaying the synthetic image FP2 that relatively widelyshows the side region of the left direction is maintained. Meanwhile, ifthe turn signal indicates a right direction in S15, S17 is carried out.

In case of performing changing a direction or moving toward a roadside,the steering wheel is minutely operated. Accordingly, there is a casewhere the winker switch of the direction instructing device 83 isreturned from the operation position to the neutral position,irrespective of the intension of the driver. Thus, the drivercontinuously operates the winker switch of the direction instructingdevice 83 in the same direction for a short time. In this case, if theviewpoint position of the virtual viewpoint VP is immediately changed inresponse to on/off of the turn signal, the viewpoint position of thesynthetic image FP2 displayed on the display 21 is frequently converted,so that seeing the synthetic image FP2 becomes difficult. Accordingly,even if the turn signal is off, the viewpoint position of the virtualviewpoint VP should be maintained until the predetermined time elapses,and the viewpoint position of the virtual viewpoint VP should bereturned to the position VPC substantially in a center of the left andthe right under the condition that the predetermined time has elapsed inthe state that the turn signal is off. Accordingly, the occasion thatseeing the synthetic image FP2 becomes difficult can be prevented.

As the predetermined time used for the determination is short, it islikely that the viewpoint position of the synthetic image FP2 isfrequently converted. As the predetermined time used for thedetermination is long, the viewpoint position of the synthetic image FP2is not easily returned to substantially the center. Accordingly, thepredetermined time is preferably set to two to four seconds.

The case where the turn signal indicates a left direction has beendescribed. However, the case where the turn signal indicates a rightdirection is different from the case where the turn signal indicates aleft direction only in terms of the left or right direction, andundergoes the same processing as that for the case where the turn signalindicates a left direction. In other words, in S17, the virtualviewpoint VP is set to the position VPR of the right side. Accordingly,as illustrated in FIG. 11, the synthetic image FP2 that more widelyshows the side region of the right direction than the left direction isgenerated and displayed on the display 21.

Subsequently, in the state that the virtual viewpoint VP is set to theposition VPR of the right side, the turn signal state is monitored(S18). If the state that the turn signal indicates a right direction ismaintained, the processing is returned to S17, so that the virtualviewpoint VP is maintained as the position VPR of the right side. If theturn signal indicates a left direction, S12 is carried out.

In S18, if the turn signal is off, measuring by the timer 12 at the timethat the turn signal becomes off is started (S19), and the turn signalstate is monitored until the predetermined time elapses from thestarting of the measuring (S20 and S21). At this time, until thepredetermined time elapses, the virtual viewpoint VP is maintained asthe position VPR of the right side. If the predetermined time haselapsed in the state that the turn signal is off (Yes in S21), theviewpoint position of the virtual viewpoint VP is returned to theposition VPC substantially in a center of the left and the right (S22).Accordingly, the synthetic image FP2 that substantially equally includesthe side regions of the left and right sides of the vehicle 9 isdisplayed.

However, if the turn signal indicates a right direction again in S20,until the predetermined time elapses from the starting of the measuring,the processing is returned to S17, so that the state that the virtualviewpoint VP is the position VPR of the right side is maintained. Inother words, displaying the synthetic image FP2 that relatively widelyshows the side region of the right direction is maintained. Meanwhile,if the turn signal indicates a left direction in S20, S12 is carriedout.

4-2. Single Image Mode

Returning to FIG. 5, a display aspect in the single image mode M12 willbe described. In the single image mode M12, the display 21 displays onlythe synthetic image FP3. The viewpoint position of the virtual viewpointVP is set to the position substantially in a center of the left and theright at the rear of the vehicle 9, and the visual field direction isset to the front direction of the vehicle 9. Accordingly, the syntheticimage FP3 shows the left and right side regions of the vehicle 9 in thestate that the vehicle 9 is viewed from the rear position of the vehicle9 to the front direction. In the case where the vehicle 9 is driven toavoid an oncoming vehicle on a narrow road or the like, both the leftand right sides of the vehicle 9 should be monitored. Accordingly, thesingle image mode M12 in the display aspect described above can beeffectively used.

In the single image mode M12 as well, the visual field direction of thesynthetic image FP3 is substantially the same as the visual fielddirection of the driver. Accordingly, the driver can intuitivelyrecognize the positional relation between the vehicle 9 and an objectdisplayed on the display 21.

If the display mode has been converted into the single image mode M12,animation expression is implemented such that the virtual viewpoint VPof the synthetic image FP3 moves in the manner that a plurality ofsynthetic images FP3 are continuously displayed. FIG. 13 is a viewshowing an example of display in the case where animation expression isimplemented in the single image mode 12. FIG. 14 is a view showingmovement of the virtual viewpoint VP in that case.

As illustrated in FIG. 14, the viewpoint position of the virtualviewpoint VP is changed by the control section 1, such that theviewpoint position of the virtual viewpoint VP is straightly moved froma position VPD corresponding to the viewpoint of the driver to aposition VPA at the rear of the vehicle 9. At this time, the syntheticimage generating section 32 generates a plurality of synthetic imagesFP3 while sequentially moving the virtual viewpoint VP from the positionVPD to the position VPA. In addition, the synthetic image generatingsection 32 generates an animation in which the virtual viewpoint VP iscontinuously moved by sequentially generating the plurality of syntheticimages FP3. Parameters to generate the plurality of synthetic images FP3are extracted by the control section 1 by Linear interpolation based onparameters for the position VPD prior to the change and parameters forthe position VPA after the change. The plurality of generated syntheticimages FP3 are output in turn to the navigation apparatus 20, andsequentially displayed on the display 21.

Accordingly, as illustrated in FIG. 13, animation expression isimplemented on the display 21, such that the virtual viewpoint VP of thesynthetic image FP3 moves from a position corresponding to the viewpointof the driver to the rear position of the vehicle 9. On the syntheticimage FP3, the image of the vehicle 9 does not appear (ST11) because aninitial viewpoint is the viewpoint of the driver. However, an image of atop portion of the vehicle 9 gradually appears (ST12 and ST13). Finally,an image of the vehicle 9 looking down the vehicle 9 from the rearappears (ST14). The animation expression is implemented for about onesecond.

In the case where the position of the virtual viewpoint VP is changed,if the virtual viewpoint VP is momentarily converted, the driver cannoteasily determine the position of the virtual viewpoint VP, from whichthe synthetic image is viewed. By implementing the animation expressionas in the present embodiment, the driver can intuitively recognize theposition of the virtual viewpoint VP, from which the synthetic image isviewed, compared to the case where the virtual viewpoint VP ismomentarily converted.

When implementing the animation expression, a position corresponding tothe viewpoint of the driver of the vehicle 9 is a reference position,such that the viewpoint position of the virtual viewpoint VP is movedfrom the reference position. Since the viewpoint position after thechange of the virtual viewpoint VP is presented based on the viewpointposition of the driver, the viewpoint position after the change of thevirtual viewpoint VP can be easily intuitively recognized. The referenceposition to start the animation expression may not be the positioncorresponding to the viewpoint of the driver, and may be a position thatcan be easily intuitively recognized by the driver. For example, thereference position may be a position directly above substantially acenter of the vehicle 9 or a substantially central position of the leftand the right of a front bumper.

The animation expression can be implemented under any circumstances,e.g., in the case where the virtual viewpoint VP is changed, as well asthe display mode is changed. For example, in the aforementioned binaryimage mode M11, even in the case where the viewpoint position of thevirtual viewpoint VP is changed in the left and right direction inresponse to operation of the direction instructing device 83, theanimation expression is preferably implemented. In any case, it ispreferable to generate a plurality of synthetic images, for whichanimation expression can be implemented through continuous display,while the position of the virtual viewpoint is sequentially moved.Parameters to generate the synthetic images may be extracted by Linearinterpolation based on parameters for a position prior to the change andparameters for a position after the change. By using the animationexpression, the driver can intuitively recognize the position of thevirtual viewpoint VP after the change.

4-3. Side Camera Mode

Returning to FIG. 5, a display aspect in the side camera mode M13 willbe described below. In the side camera mode, the display 12 displaysonly the side image FP4. The side image FP4 is not a synthetic imagefrom the virtual viewpoint VP, but is a display image obtained in themanner that a captured image obtained from capturing in the side cameras52 of the left side is adjusted by the image adjusting section 31 to bea display image.

For example, the position of the driver's seat in the vehicle 9 of thepresent embodiment is the right side. Accordingly, the outside region ofthe front fender 94 on the left side of the vehicle 9, which is oppositeto the position of the driver's seat, may be easily blinded.Accordingly, in the side camera mode M13, the outside region of thefront fender 94 of the left side is enlarged and presented. Accordingly,the state of an object existing in the blinded region can be easilyrecognized, compared to the other display modes.

As illustrated in FIG. 15, in the side camera mode M13, the convertingswitch 85 is pressed, so that the scope to be displayed on the display21 can be converted. Specifically, conversion between the side imageFP4, which enlarges and presents a region near a front wheel 96 of theleft side of the vehicle 9, and the side image FP5, which enlarges andpresents the rear region rather than the front wheel 96, is possible.

5. Back Mode

Hereinafter, a display aspect of the back mode M2, which is an operationmode when the position of the shift lever is “R (reversing),” will bedescribed. FIG. 16 is a view showing transition of a display mode in theback mode M2. The back mode M2 includes four display modes, i.e., astandard mode M21, a wide mode M22, a synthetic standard mode M23, and asynthetic high angle mode M24. The modes are different in a displayaspect. By performing predetermined operation, the driver can selectcertain one display mode and set the selected display mode as a currentdisplay mode (hereinafter, referred to as the “current mode”).

Specifically, when the converting switch 85 is pressed, the current modeis set to the standard mode M21, the wide mode M22, and the syntheticstandard mode M23 in this order. If the synthetic standard mode M23 isthe current mode, when the converting switch 85 is pressed, the standardmode M21 is set as the current mode again. Instead of the convertingswitch 85, a command button on the screen may be pressed for conversion.

If the synthetic standard mode M23 is the current mode, when a viewpointconverting button CB1 displayed as a command button on the screen of thedisplay 21 is pressed, the synthetic high angle mode M24 is set as thecurrent mode. Even if the synthetic high angle mode M24 is the currentmode, when the viewpoint converting button CB1 displayed on the screenof the display 21 is pressed, the synthetic standard mode M23 is set asthe current mode. If the synthetic high angle mode M24 is the currentmode, when the converting switch 85 is pressed, the standard mode M21 isset as the current mode.

In the back mode M2, a display image corresponding to the current modeis generated by the image processing section 3 and displayed on thedisplay 21. If the standard mode M21 and the wide mode M22 are thecurrent mode, the display 21 displays a display image that only includesback images BP1 and BP2 obtained from capturing in the back camera 53.If the synthetic standard mode M23 is the current mode, the display 21displays a display image that includes a synthetic image BP4 viewed fromthe virtual viewpoint VP and a back image BPS obtained from capturing inthe back camera 53 side by side. If the synthetic high angle mode M24 isthe current mode, instead of the back image BP5 in the syntheticstandard mode M23, a synthetic image BP6 viewed from the virtualviewpoint VP is displayed.

5-1. Standard Mode

As illustrated in FIG. 16, in the standard mode M21, the display 21 onlydisplays the back image BP1. The back image BP1 is not a synthetic imagefrom the virtual viewpoint VP, but is a display image obtained in themanner that a captured image obtained from capturing in the back camera53 is adjusted by the image adjusting section 31 to be a display image.As illustrated in FIG. 17, a horizontal angle of the visual field scopeof the back image BP1 is 135°. In the standard mode M21, the rear regionof the vehicle 9 is presented in a natural aspect,

In the back image BP1, a guide line GL presenting an expected path uponreversing of the vehicle 9 is displayed in an overlapping manner. Theguide line GL is moved in accordance with a rotation direction and arotation angle of the steering wheel input from the steering sensor 84.Accordingly, based on the guide line GL, the driver can reverse thevehicle 9.

5-2. Wide Mode

As illustrated in FIG. 16, even in the wide mode M22, the display 21only displays the back image BP2. The back image BP2 is not a syntheticimage from the virtual viewpoint VP, but is a display image obtained inthe manner that a captured image obtained from capturing in the backcamera 53 is adjusted in the image adjusting section 31 to be a displayimage. In the back image BP2 as well, the guide line GL indicating anexpected path upon reversing of the vehicle 9 is displayed in anoverlapping manner.

As illustrated in FIG. 18, a horizontal angle of the visual field scopeof the back image BP2 is 180°. An object having a larger scope in thehorizontal direction than the standard mode M21 can be monitored.Accordingly, in case of head-on parking, when the vehicle is reversedfrom the parking lot, the driver can monitor the left and right regionsof the rear side that may be easily blinded, by using the wide mode M22in the display aspect described above.

5-3. Synthetic Standard Mode

FIG. 19 is a view showing an example of a display image to be displayedon the display 21 in the synthetic mode M23, As illustrated in FIG. 19,on a display image in the synthetic standard mode M23, the syntheticimage BP4 is disposed at the left side, and the back image BPS isdisposed at the right side. The synthetic image BP4 is a synthetic imageviewed from the virtual viewpoint VP looking down the entire peripheryof the vehicle 9. The back image BPS is not a synthetic image from thevirtual viewpoint VP, but is a display image obtained in the manner thata captured image obtained from capturing in the back camera 53 isadjusted in the image adjusting section 31 to be a display image. Ahorizontal angle of the visual field scope of the back image BP5 is135°.

The driver sees the display image of the synthetic standard mode M23 inthe display aspect described above, so that he/she can monitor theentire periphery of the vehicle 9 and the rear region of the vehicle 9at the same time. Accordingly, the driver can safely reverse the vehicle9 while recognizing an object around the entire circumference of thevehicle 9.

5-4. Synthetic High Angle Mode

FIG. 20 is a view showing an example of a display image to be displayedon the display 21 in the synthetic high angle mode M24. As illustratedin FIG. 20, the synthetic image BP4 viewed from the virtual viewpoint VPlooking down the entire periphery of the vehicle 9 is disposed at theleft side of the display image in the synthetic high angle mode M24, asin the synthetic standard mode M23. The synthetic image BP6 viewed fromthe virtual viewpoint VP substantially directly looking down thevicinity of the rear end of the vehicle 9 is disposed at the right sideof the display image.

As illustrated in FIG. 21, the viewpoint position of the virtualviewpoint VP of the synthetic image BP6 is set to the positionsubstantially directly above the rear end of the vehicle 9. The visualfield direction is set to substantially a direct downward direction.Accordingly, on the synthetic image BP6, a region near the rear end ofthe vehicle 9 is enlarged and presented in the state that the region islooked down from the upward direction to substantially the directdownward direction. On the synthetic image BP6, a rear direction of thevehicle 9, which is the driving direction upon reversing of the vehicle9, is an upper side direction of the image.

The driver sees the display image of the synthetic high angle mode M24in the display aspect described above, so that he/she can easily monitorclearance between the vehicle 9 and an object around the vehicle 9, inparticular, clearance with an object existing near the rear end of thevehicle 9. Meanwhile, it is difficult to monitor an object existingapart from the vehicle 9 in the rear region of the vehicle 9, which isthe driving direction upon reversing of the vehicle 9. Accordingly, thesynthetic high angle mode M24 is a display mode that can be effectivelyused under a special circumstance such as final adjustment of a parkingposition of the vehicle 9 in the case where the vehicle 9 is reversedupon parking.

5-5. Angle Adjustment

For the synthetic image 13P4 disposed at the left side in the syntheticstandard mode M23 (refer to FIG. 19) and the synthetic high angle modeM24 (refer to FIG. 20), the viewpoint position of the virtual viewpointVP can be set to a position desired by the driver. In the syntheticstandard mode M23 or the synthetic high angle mode 24, a setting buttonCB2 displayed as a command button on the screen is pressed, so that asetting screen to set the viewpoint position of the virtual viewpoint VPis displayed.

FIGS. 22 and 23 are views showing the setting screen of the virtualviewpoint VP. The setting screen shows an indicator presenting theposition of the virtual viewpoint VP to the vehicle 9, together withillustration of the side surface of the vehicle 9. The command buttonsCB4 and CB5 on the screen are pressed so that the indicator can bemoved. The position of the moved indicator to the illustration of thevehicle 9 is set as the viewpoint position of the virtual viewpoint VP.In this case, the visual field direction of the virtual viewpoint VP isset to be toward substantially a center 9 c of the vehicle 9. FIG. 22 isa view showing an example of the case where the viewpoint position ofthe virtual viewpoint VP is set to a position directly abovesubstantially a center of the vehicle 9. FIG. 23 is a view showing anexample of the case where the viewpoint position of the virtualviewpoint VP is set to the rear position of the vehicle 9.

The left side of the setting screen displays the synthetic image BP7 inthe case where the position of the indicator is the virtual viewpointVP. Accordingly, by seeing the setting screen, it can be easilydetermined which synthetic image BP7 is obtained in the case where thevirtual viewpoint VP is moved. Accordingly, the driver can move thevirtual viewpoint VP to his/her desired position.

When the finish button CB displayed as a command button on the settingscreen is pressed, the set contents are reflected on the display of thesynthetic standard mode M23 and the synthetic high angle mode 24. Forexample, when the finish button BC3 on the setting screen as illustratedin FIG. 23 is pressed, the vehicle 9 is presented on the synthetic imageBP4 at the left side of the display image in the state that the vehicle9 is viewed from the rear side of the vehicle 9, as illustrated in FIG.24. Since the viewpoint position of the virtual viewpoint VP can be set,the driver can recognize the positional relation between the vehicle 9and an object around the vehicle 9 from a desired angle upon reversingof the vehicle 9.

5-6. Current Mode Setting

In the back mode M2, there are four display modes different from eachother. An instruction from the driver by using the converting switch 85or others is received. In accordance with the instruction, one displaymode is set to the current mode. In general, the driver frequently usesone desired display mode among the four display modes in accordance withhis/her favorites or an environment of a parking lot that he/she usuallyuses. If a display mode desired by the driver needs to be set as thecurrent mode each time the vehicle 9 is reversed, the operation willbecome complicated.

Accordingly, the image display system 100 stores a display mode whichhas been recently set as the current mode in the back mode M2. When theoperation mode becomes the back mode M2 next time, the control section 1sets the display mode which has been recently set as the current mode,as the current mode immediately after the operation mode becomes theback mode M2. Accordingly, the driver does not need to perform thecomplicated operation to select his/her desired display mode each timethe vehicle 9 is reversed.

FIG. 25 is a view showing flow of processing to store informationindicating the current mode that has been most recently set. Theprocessing is repeatedly carried out by the control section 1, in thecase where the operation mode is the back mode M2.

First, it is determined whether or not the current mode has beenconverted into another display mode (S31). If the current mode has beenconverted into another display mode, mode information indicating thecurrent mode after the conversion is stored in the non-volatile memory11 (S32). Since the processing is carried out each time the current modeis converted, mode information indicating the display mode that has beenrecently set as the current mode is stored in the non-volatile memory11. The mode information is stored in the non-volatile memory 11 whenthe operation mode is an operation mode other than the back mode M2(when the transmission of the vehicle 9 is at a position other than “R(reversing)”) or when the power of the image display system 100 is off.

FIG. 26 is a view showing processing flow of time to start the back modeM2. The processing is carried out by the control section 1 when thetransmission of the vehicle 9 is operated to be positioned at “R(reversing),” and when the operation mode is the back mode M2.

First, the mode information stored in the non-volatile memory 11 is read(S41). It is determined what is the display mode indicated by the readmode information (S42).

If the display mode indicated by the mode information is a display modeother than the synthetic high angle mode M24 (No in S42), the displaymode indicated by the mode information is set as the current mode (S43).If the display mode indicated by the mode information is the synthetichigh angle mode M24 (Yes in S42), the synthetic standard mode M23 is setas the current mode (S44).

The display mode that has been recently set as the current mode is inprinciple set as the current mode immediately after the operation modebecomes the back mode M2. However, if the display mode that has beenrecently set as the current mode is the synthetic high angle mode M24,the synthetic standard mode M23, and not the synthetic high angle modeM24, is set as the current mode immediately after the operation modebecomes the back mode M2. Since the synthetic high angle mode M24 isusually used when the parking position of the vehicle 9 is finallyadjusted, the synthetic high angle mode M24 is rarely used at the timeof starting reversing of the vehicle 9. Accordingly, if the display modethat has been recently set as the current mode is the synthetic highangle mode M24, on exception, another display mode is set as the currentmode immediately after the operation mode becomes the back mode M2, sothat the complicated operation to change the current mode from thesynthetic high angle mode M24 to another display mode is unnecessary.

Meanwhile, the processing to exceptionally treat the synthetic highangle mode M24 may be carried out by a processing different from thatillustrated in FIGS. 25 and 26.

FIG. 27 is a view showing another example of flow of processing to storeinformation indicating the recent current mode. The processing also isrepeatedly carried out by the control section 1 when the operation modeis the back mode M2.

First, it is determined whether or not the current mode has beenconverted into another display mode (S51). If the current mode has beenconverted into another display mode, it is determined what is thecurrent mode after the conversion (S52).

If the current mode after the conversion is a display mode other thanthe synthetic high angle mode M24 (No in S52), mode informationindicating the current mode after the conversion is stored in thenon-volatile memory 11 (S53). If the current mode after the conversionis the synthetic high angle mode M24 (Yes S52), mode informationindicating the synthetic standard mode M23 is stored in the non-volatilememory 11 (S54).

Accordingly, mode information indicating the display mode that has beenrecently set as the current mode is in principle stored in thenon-volatile memory 11. However, if the current mode that has beenrecently set is the synthetic high angle mode M24, on exception, modeinformation indicating the synthetic standard mode M23 is stored.

FIG. 28 is a view showing processing flow of time to start the back modeM2 in carrying out the processing of FIG. 27. The processing also iscarried out by the control section 1 when the transmission of thevehicle 9 is operated to be positioned at “R (reversing)” such that theoperation mode becomes the back mode M2.

First, mode information stored in the non-volatile memory 11 is read(S61). The display mode indicated by the read mode information is set asthe current mode (S62). In the processing as well, if the display modethat has been recently set as the current mode is the synthetic highangle mode M24, on exception, another display mode may be set as thecurrent mode immediately after the operation mode becomes the back modeM2. As a result, the complicated operation to change the current modefrom the synthetic high angle mode M24 to another display mode isunnecessary.

6. Modified Embodiment

An embodiment of the present invention has been described. However, thepresent invention is not limited to the embodiment that has beendescribed. Various modifications to the present invention may be made.Hereinafter, modified embodiments of the present invention will bedescribed. Of course, the modifications set forth below may be properlycombined.

In the embodiment that has been described, the image generatingapparatus 10 and the navigation apparatus 20 are different. However, thenavigation apparatus 20 and the image generating apparatus 10 may bedisposed in the same housing to construct an integrated apparatus.

In the embodiment that has been described, the display apparatus thatdisplays a display image generated in the image generating apparatus 10is the navigation apparatus 20. However, the display apparatus may be ageneral display apparatus that has not a special function such as anavigation function.

In the embodiment that has been described, part of the function that isrealized by the control section 1 of the image generating apparatus 10may be realized by the control section 23 of the navigation apparatus20.

Signals from the shift sensor 81, the vehicle speed sensor 82, thedirection instructing device 83, the steering sensor 84, and theconverting switch 85 are input into the image generating apparatus 10.However, part or all of the signals may be input into the navigationapparatus 20. In that case, part or all of the signals may be input intothe control section 1 of the image generating apparatus 10 through thecommunication section 42.

In the embodiment that has been described, an instruction of a directiondesired by the driver is input from the direction instructing device 83.However, the instruction may be input by other means. For example,movement of a viewpoint of the driver is detected from an image obtainedfrom capturing the driver's eyes. From the detection results, adirection instruction intended by the driver may be input.

In the embodiment that has been described, the specific display modethat is exceptionally treated in the back mode M2 is the synthetic highangle mode M24. However, another display mode, and not the synthetichigh angle mode M24, may be set as the specific display mode. Forexample, a display mode that only displays an image from a virtualviewpoint substantially directly looking down the vicinity of the rearend of the vehicle 9 may be the specific display mode. Preferably, adisplay mode in an aspect used under a special condition such as finaladjustment of a parking position is the specific display mode.

In the embodiment that has been described, various functions areaccomplished by software through calculation processing of the CPU inaccordance with programs. However, part of the functions may beaccomplished by an electrical hardware circuit. Reversely, part of thefunction that is accomplished by a hardware circuit may be accomplishedby software.

The present invention is based on Japanese patent applications filed onMay 29, 2009 (Japanese Patent Application No. 2009-130100), thedisclosures of which are herein incorporated by reference.

DESCRIPTION OF REFERENCE NUMERALS

1 control section

3 image processing section

5 capturing section

10 image generating apparatus

11 non-volatile memory

21 display

32 synthetic image generating section

42 communication section

100 image display system

1. An image generating apparatus that generates an image to be displayedon a display apparatus mounted on a vehicle, the image generatingapparatus comprising: a synthetic image generating section thatgenerates a synthetic image around the vehicle based on a plurality ofimages of the periphery of the vehicle took by a plurality of cameras,the synthetic image being viewed from a virtual viewpoint which isdisposed behind the vehicle and is directed to the front side of thevehicle; an output section that outputs the generated synthetic image tothe display apparatus; and an input section that inputs a directionindication of a driver of the vehicle, wherein the synthetic imagegenerating section: generates a first synthetic image in which left sidearea of the vehicle is displayed in substantially the same size as rightside area of the vehicle when the direction indication is not input bythe input section; and generates a second synthetic image in which oneside area of the vehicle, which is indicated by the direction indicationis displayed larger in size than another side area of the vehicle whenthe direction indication is input by the input section.
 2. The imagegenerating apparatus as set forth in claim 1, wherein the syntheticimage generating section continues to generate the second syntheticimage for a predetermined period when the input section stops inputtingthe direction indication, and wherein the synthetic image generatingsection starts generating the first synthetic image after thepredetermined period when the direction indication is not input duringthe predetermined period.
 3. The image generating apparatus as set forthin claim 1, further comprising a display image generating section thatgenerates a display image including a front image took by a cameraprovided at the front side of the vehicle and the synthetic imagegenerated by the synthetic image generating section, wherein the outputsection outputs the generated display image to the display apparatus. 4.The image generating apparatus as set forth in claim 1, wherein whenchanging the virtual viewpoint of the synthetic image from a firstposition to a second position, the synthetic image generating sectionmoves the virtual viewpoint from the first position to the secondposition in a stepwise manner to generate a plurality of syntheticimages for creating an animation in which the virtual viewpoint is movedin a continuous manner.
 5. An image generating apparatus that generatesan image to be displayed on a display apparatus mounted on a vehicle,the image generating apparatus comprising: a synthetic image generatingsection that generates a synthetic image around the vehicle based on aplurality of images of the periphery of the vehicle took by a pluralityof cameras, the synthetic image being viewed from a virtual viewpointwhich is disposed behind the vehicle and is directed to the front sideof the vehicle, and including a right side area and a left side area ofthe vehicle; a display image generating section that generates a displayimage including a front image took by a camera provided at the frontside of the vehicle and the synthetic image generated by the syntheticimage generating section; and an output section that outputs thegenerated display image to the display apparatus.
 6. An image generatingapparatus that generates an image to be displayed on a display apparatusmounted on a vehicle, the image generating apparatus comprising: asynthetic image generating section that generates a synthetic imagebeing viewed from a virtual viewpoint based on a plurality of images ofthe periphery of the vehicle took by a plurality of cameras; and anoutput section that outputs the generated synthetic image to the displayapparatus, wherein when changing the virtual viewpoint of the syntheticimage from a first position to a second position, the synthetic imagegenerating section moves the virtual viewpoint from the first positionto the second position in a stepwise manner to generate a plurality ofsynthetic images for creating an animation in which the virtualviewpoint is moved in a continuous manner.
 7. The image generatingapparatus as set forth in claim 6, wherein the synthetic imagegenerating section changes the virtual viewpoint from a referenceposition.
 8. The image generating apparatus as set forth in claim 7,wherein the reference position is a position corresponding to aviewpoint of a driver of the vehicle.
 9. An image display system to bemounted on a vehicle, the image displaying system comprising: the imagegenerating apparatus as set forth in claim 1; and a display apparatusthat displays an image generated by the image generating apparatus. 10.An image display system to be mounted on a vehicle, the image displayingsystem comprising: the image generating apparatus as set forth in claim5; and a display apparatus that displays an image generated by the imagegenerating apparatus.
 11. An image display system to be mounted on avehicle, the image displaying system comprising: the image generatingapparatus as set forth in claim 6; and a display apparatus that displaysan image generated by the image generating apparatus.